It is known, in the rolling of continuous members, e.g. wire, to control the cooling with the aid of temperature measurements utilizing, for example, a pyrometer to measure the rolling wire temperature following the rolling process.
However, the measured value of the temperature is largely a function of the medium between the wire and the pyrometer, e.g. is sensitive to the presence of the cooling water, steam or the like. As a result, the measuring location must be provided downstream of the cooling stretch and hence the measured temperature does not permit precision control of the cooling system.
In order to provide precision control of the cooling temperature, it is necessary to measure the temperature of the wire free from such influences during the cooling operation. However, it has been found that it is impractical or impossible to subdivide a cooling process into a multiplicity of cooling zones with temperature measurement of this type following each zone so as to be effected downstream thereof.
The measurements are also found to be adversely affected by surface impurities on the rolled wire.
Another process for measuring the rolled wire temperature is described in German Pat. No. 1,452,345. In this method the temperature of the wire surface is not measured, but rather the heat content of the wire is determined by measuring the thermal radiation from the wire.
This can be achieved with an electrical resistor which surrounds the wire and serves as a temperature sensor.
The disadvantage of this measurement approach is that the measurement does not always reflect the surface temperature so that excessive cooling might detrimentally affect the surface structure of the wire or insufficient cooling which may not be metallurgically satisfactory can result.